FI71090B - FOERFARANDE OCH APPARAT FOER AOSTADKOMMANDE AV FOERSEGLINGAR - Google Patents

Description

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C (45) Patent granted Γ.7 t ^ rt .7, C If t '3 t Γ · ί' '1 1 QO0 ^ ^ ^ (51) Kv.lk. «/ Int.ci. * B 31 B 1 / 60, B 65 B 51/22 EN NL AN D (21) P * examination application - Patentansöknlng 772966 (22) Date of application - Aniökningsdag 07 · 10.77 (EN) (23) Starting date - Giltighetsdag 07.10.77 (41) Published public - Blivit offentllg 09.04.78

National Board of Patents and Registration (44) Date of publication and date of publication. - 1 4. 08.86

Patent- oeh registerstyrelsen Ansökan utlagd oth utl.skrlften publicerad (86) Kv. application - Int. trap (32) (33) (31) Claim claimed - Begärd prlorltet 08.10.76 USA (US) 730765 (71) Ex-Ce11-0 Corporation, 2855 Coolidge, Troy, Michigan 48084, USA (US) (72) Jack M Neumayer, Wixom, Michigan, Ivan Leon Kauffman, Union Lake,

Michigan, USA (US) (7 * 0 Oy Kolster Ab (54) Method and apparatus for achieving the chemical function -Förfarande och apparat för ästadkommande av försegl Ingar

The present invention relates generally to packaging methods and apparatus, and more particularly to a method and apparatus for providing a certain barrier function between the layers of a can made of thermoplastic coated cardboard or similar material. In this case, po. the thermoplastic material of the layers is activated by kit heat from an oscillating welding horn and allowed to cool and solidify under pressure, thereby "locking" the layers and between them.

The type of can to which the invention mainly relates is made on both sides of a thermoplastic material, e.g. polyethylene, coated with cardboard. The paving material is used both as a layer of moisture km and as the first air that receives po. when sealing cardboard seams, closures, etc., the packaging becomes liquid-tight, in which case it can be used e.g. a milk carton. One example po. of the general type are disclosed in U.S. Patent Nos. 3,120,089, 3,309,841 and 3,910,014.

2 71090 Until now, thermoplastic-coated cartons have been sealed by heat-activating the coating material so that the coating material has been allowed to flow over the parts to be joined or sealed, after which the end of the can is sealed together. Once the thermoplastic material between the layers has cooled and solidified, the layers are "melted together" and locked. Complex and expensive equipment is needed to generate the fairly large amount of energy required for this purpose. In addition, there is also a need for complex and expensive equipment and methods for conducting heat away from the workplace in question. Examples of such a general type of packaging device are disclosed in U.S. Patents 3,002,328, 3,120,089, 3,166,994, 3,187,647, 3,239,995 and 3,309,841.

U.S. Patents 3,905,280 and 3,910,014 disclose a device for closing the ends and side seams of thermoplastic coated cans. The mechanical energy is then converted into "localized" thermal energy in order to reduce the amount of heat and energy required and to avoid the need for expensive systems and methods to dissipate excess heat. U.S. Pat. No. 3,526,792 relates to an ultrasonic transducer which converts electrical energy into mechanical energy and which is equipped with a so-called a centering horn11a that concentrates (converts) mechanical energy into oscillations having a desired frequency. Em, according to U.S. Patents 3,905,280 and 3,910,014, po. the horn oscillates at a predetermined frequency when activated and operatively associated with a particular support member so that layers of thermoplastic coated paperboard are compressed between the working surface of the horn and the support surface of the 1st stop of the support device in question.

When po. pressing is performed, the vibrations of the horn generate enough frictional heat to activate the thermoplastic coating po. layers so that their thermoplastic material flows together.

When the vibration stops, the thermoplastic cools and solidifies, and then the layers are joined together and glued together.

A further advantage of sound wave vibration welding is that it cannot be soiled or wetted due to the surface-focused energy supply. If the heat is applied directly to the place in question and not by vibration welding, more energy must be supplied so that the moisture present in the surfaces to be sealed is evaporated before the thermoplastic material can be heated sufficiently for activation. If the humidity in the above-mentioned surfaces varies in quantity, the amount of thermal energy must also be changed accordingly.

3,71090

In addition, the humidity causes the amount of thermal energy required to be much higher than the amount of heat required to activate the thermoplastic when the streams are dry. This can be avoided by vibration welding, as the centralized use of energy significantly reduces the amount of energy required to evaporate moisture.

When sealing thermoplastic-coated cartons using vibration welding, there are two steps: the first is an activation step during which the friction of the vibrating horn generates enough heat to activate the thermoplastic, and the second is a cooling step during which the layers are compressed and the "classification function" occurs.

A significant factor in determining the production rate is the time required for the shutdown operation. Po. horn has heretofore been used for both activation and compression during the cooling phase. When the horn is used in both stages of work, it involves a complete cycle of "locking" between the layers of paperboard, (1) pushing the work surfaces into the abutment (or other support part) and the horn so that they face each other on opposite sides of the interlocking and "interlocking" layers. (2) activating the thermoplastic coating in the interlayer layers with frictional heat from the activated horn so that the coating layers are "run" together; (3) cooling and solidifying the previously activated thermoplastic material po. with the material continuously between the horn and abutment surfaces "released" from activation; and (4) separating the horn and abutment surfaces to separate the paperboard layers after sealing has occurred. The time taken for this per cycle is about 1/2 to 2 seconds or slightly more, depending on the strength of the board and thermoplastic coating, the number of layers and the surface area.

In this type of vibration welding operation, the horn is usually pressure controlled to generate vibration. When the work surface of the horn is pushed to a position that contacts the layers of paperboard to be joined together, the horn begins to vibrate when the horn guide portion "reads" a predetermined pressure from the work surface of the horn. In a high-power packaging system, the time used for the 1. lock-locking operation is mainly determined by the speed at which the welding must go through the cycle, depending on the speed of other machines in the cone on the same production line. The welding device must therefore be arranged in a work line comprising machines for making finished cans from plain material (cardboard), e.g. the machines mentioned in U.S. Patents 3,599,5U1 and 3,937,131 and the filling and sealing machine according to U.S. Patent 3,910,01M.

An American patent (Pat. No. 652,916) relates to an apparatus and method for vibrating welding thermoplastic coated cardboard cans. Po. in the method, the vibrating welding horn is "tuned" to cause vibration before it contacts the layers to be sealed. The U.S. patent (Pat. No. 6,90521) again relates to a method and apparatus for providing a sealing function in thermoplastic-coated paperboard cartons (cans) by vibration welding. In this case, an oscillating welding horn is used to activate the thermoplastic material of the board. The board is then pushed to a pressing and cooling station with the thermoplastic continuously activated. The activated layers are compressed. the station is then joined together and cooled, creating a "lock".

According to a design alternative involving activation and cooling of the thermoplastic coating at one station and compression of the layers at another station (i.e., sound joining at two stations), it has been found advantageous to allow the activated thermoplastic to be partially solidified under at least some conditions. The horn is "tuned" so that it begins to vibrate before it is pressed into the paperboard layers. At the end of the act, the horn stops vibrating, but the horn remains compressed po. layers so that the activated thermoplast! partially solidifies, at which point the actual closing function begins. The horn is then retracted and the can moves to a pressing and cooling station where it is sealed and joined, i.e. the layers in question are compressed and cooled until the activated thermoplastic solidifies completely.

It is an object of the present invention to provide an improved method and an improved device by means of which vibration welding provides a sealed function between the layers of a thermally coated can or the like. In this case, the thermoplastic coating is activated at the second station and cooled and solidified completely at the second anemia. s ui kutoi mi n non a L k a a n s a a rn i ·; e k y 5.

5,71090

In addition, the invention aims to develop a method and a device for closing the ends of cans made of thermoplastic-coated cardboard or the like. In this case, the thermoplastic coating is activated by vibration welding at a certain point on the Akti voint.iasema and then allowed to partially solidify at the same station, after which the layers (the thermoplastic is already partially activated) are pushed to the compression and "locking station", where they are compressed until activated. the thermoplastic cools and solidifies completely, giving po. a "lock" is generated.

The object required by the invention is achieved by the method further defined in the appended claim 1.

The invention also relates to a device with which the above-mentioned method can be implemented. The main features of this device are again apparent from claims 2-15.

The invention will be described in more detail below with reference to the accompanying drawings, which illustrate some exemplary embodiments.

Figure 1 is an end projection of a device according to the invention, Figure? is taken along line 2-2 of Figure 1, Figure 3 is taken along line 3-3 of Figure 2, Figure 4 is an enlarged view of a portion of the device of Figure 1, Figure 5 is a section along line 5-5 of Figure 1, Figure 6 is a top view of the response , Fig. 7 is a sectional view taken along line 7-7 of Fig. 6, Fig. 8 is a perspective view of a portion of a thermoplastic-coated can with the top completely open, Fig. 9 is a perspective view of the dowel of Fig. 8 after the folding step; to the final closed position), Fig. 10 is a perspective view of the can of Figs. 8 and 9, the end of which is now completely closed (one closure strip and locking nozzles extend mainly axially from the closed end before the "locking step"), Fig. 11 is a perspective view of the can after locking. the strips are in place and Figure 12 illustrates po. cans when the locking strip is bent flat.

The invention thus mainly relates to the closing and locking of cardboard cans coated with a thermoplastic material. The can is then of the general type shown in Figures 8-12. It should now be noted, however, that the invention not only requires the use of a particular type of can, but is also applicable to the cans of U.S. Patents 3,120,335 and 3,905,280. The can shown in Figures 8-12 is taken as an example only and is of a type similar to U.S. Patent 3,910,014.

The can shown in Figures 8-12 is marked C. Can C has a thermoplastic coating. The can may be cardboard or similar material coated with a thermoplastic, e.g. polyethylene. The can can be manufactured in the form shown in Fig. 8 by already known machines related to the above-mentioned patents. The body of the can C is tubular and rectangular in cross-section, so that it has four side fields (sides) marked 1, 2, 3 and 4. The side sealing strip is marked 5: 11a. It is turned inwards from field 4 and connected to the inner surface of field 1.

In Fig. 8, the top of the can is completely open and has front, rear and side fields 6, 7, 8 and 9 (end closure fields) which po. in the figure departing from the axial canister tubular body. The side fields 8 and 9 have three triangular segments 13, 14 and 15 (formed along the bending lines 10, 11 and 12). The triangular segment 15 is a central segment, one side of which goes along the bending line 12. The locking strip 18 is at the upper end of the side field 9.

It is separated by a bending line from 16 triangular segments. In the center of the strip 18 there is a bending line 17 which provides an inward angle 17 which overlaps with the corresponding angle 17 of the side field 8 when the top of the can is bent and locked in the closed position, as will be described in more detail below.

The front field 6 has a bending line 20 which forms a triangular segment adjacent to the side field 8, whereby a pouring spout is formed when the full can is opened.

The lower edge of the field 6 is connected to the frame field 3 by a bending line 19, and at the upper edge of the front field there is a protruding locking strip 22, the lower edge of which is a bending line 21.

The rear field 7 has a bending line 23 corresponding to the bending line 20 of the front field 6 and correspondingly forming a triangular segment adjacent to the side field 8. The rear field 7 also has a locking strip 25 which starts from the bending line 24 at the upper end of the rear closing field 7. From the strip 25, a closure strip 26 extends upwards, the part between the ends of which is a tear strip 27. The tear strip 27 is delimited by two rows of perforations.

7 71090

When the can C is made in the position shown in Fig. 8, with its upper part fully open and leaving it axially from the tubular body of the can, the closure part can be closed, locked and bent to the position illustrated in Fig. 12. In it, the end of the can is flat, and the front and rear closing fields 6 and 7 are on the end of the can and the closing strip 26 is on the front field 6. When the tear strip 27 is removed, the edges 30 and 31 of the closure part can be pressed upwards to break the closure structure 28. The triangular segments 13, 14 and 15 (side field 8) then form a pouring spout with the triangular segments delimited by the bending lines 20 and 23 in the front and rear fields 6 £ 7.

The method of closing the closure portion at the upper end of the can C from the open position shown in Fig. 8 to the closed position shown in Fig. 12 first comprises a "pre-breaking step". This means that the side fields 7 and 8 are pressed slightly inwards, so that the triangular segments are initially bent along the lines 10, 11, 12 and 17 to such an extent that the side fields turn inwards when the front and rear fields are pushed together. This "fractionation operation" is described in detail in U.S. Patent 3,910,014 and can be performed either before or after filling the can with milk or other liquid. After the breaking phase, the front and rear fields 6 and 7 are turned opposite (Fig. 9), whereby the side fields 8 and 9 have to be pushed inwards under the front and rear fields 6 and 7. The closing flow continues until the lower edges of the strips 18, 22 and 25 are brought together along the bending lines 16, 21 and 24 so that the front and rear fields 6 and 7 are approximately on top of the can (Fig. 10). When po. the fields are in this position, the locking strips are "welded" by sound along the strips in the shaded area 28 in Figures 11 and 12. After this welding operation, the strip 26 is heated from its front field 6 end, after which it (26) and the locking strips 18, 22 and 25 are bent downwards to the position of Fig. 12. The closure strip 26 is now heated at the second end as described in U.S. Patent 3,910,014 so that the tear strip 27 does not adhere to the front field 6.

The device according to the invention can be used to close and lock the types of cans shown in Figures 8-12 when the can is pre-bent and filled. Figures 1-4 show an activation and locking device for closing and locking (welding) can C, indicated by the number 40. The bottoms of the can are on top of the support bar 42 at 8,71090 and move along it by means of a transport chain 44. The chains 44 are provided with fingers 46 that engage the cans. The structure of the transport chains and fingers 46 may be similar to that described in U.S. Patent 3,910,014. The chains 44 are mounted on the sprocket 48 and push the cans C to the left, i.e. in the direction indicated by the arrows 50 in Figures 2 and 3.

Figure 3 shows seven different positions of the can: C-1, C-2, C-3, C-4, 05, 06 and 07. In position OI, the top of the can is approximately in the position of Figure 9, i.e. it is already slightly folded.

As the can moves to the C-2 position, its front and rear fields 6 and 7 are already attached to opposite edges 53 of the closure plates 52 forming a closure groove 55. It tapers inward and downward from the inlet ends 54 of the edges 53 to the outlet ends 56 of each closure 52. provided mounting flanges 57 secured to the support member 61 by mounting members 59 (Figure 2).

As the cans move from the wide end of the closure groove 55 to the cabbage end of the support member 61, the groove edges 53 enclose the front and rear fields 6 and 7 of the can head. This position is shown in Figure 3 at C-4.

The cans are then pushed to the activation station (reference number 58, Figure 3). In Figure 3, point C-5 illustrates the location of the can at the above location. In the same figure, the pressing and locking position is marked with 60 and the position of the can with C-6 at this point. When the can is pushed from position C-6 to position C-7, its upper end closure is in the position shown in Fig. 11. The upper end is closed (Fig. 12) by a device which, however, does not belong to po. invention.

The device of Figures 1-3 has two production lines located on opposite sides of its longitudinal axis. In Figure 2, the activation and locking device is indicated by 40 'and the closure plates by reference numeral 52' (second production line). The device 40 * and the closure plates 52 'correspond to the device 40 and the closure plates 52, so only these will be described in detail. A production line with device 40 'and plates 52 * is shown only in Figure 2.

Referring to Figures 1 and 4, a vibration-1 sound wave type welding unit 62 attached to a support bracket 65 is seen in the device 40. The unit 62 may be made in accordance with U.S. Patent 3,910,014 and comprises a centering horn 63 with a flat, leaf-like and a work surface 66 comprising a portion 64 (Figure 5). The work surface 66 is a surface in contact with the layers of the closure portion of the can head. In the special structure shown in Figures 8-12 (can C), the work surface 66 9 71090 contacts the upper, rearmost closing field 7 of the strip 2 (Figure 12).

The welding device 62 has a housing for the transducer device. Po. the device converts the electrical energy into mechanical energy and causes the horn 63, 64 to oscillate at the desired frequency.

The device 40 also has a support member in the form of a stop 68 with a work surface 70 which contacts the layers of the closure part of the can end. In the case of can C shown in Figures 8-12, the working surface 70 of the stop 68 contacts the outer surface of the locking strip 22. When the working surface 66 of the horn sheet 64 contacts the strip 25, the thermoplastic coating of the layers of the can is activated along the strips 28 shown in Figures 11-12.

The abutment 68 is a plate portion with a work surface 70 extending obliquely downwards and to the left (Fig. 1). The abutment 68 (Fig. 6) comprises two separate transverse passages 72 communicating with the longitudinal passage 74 so that water or other coolant can circulate through the abutment 68 as the device 40 operates.

The device 40 also has a holding portion 76. It is an elongate, disk-memoryable portion parallel to and above the work surface 70 of the stop 68. The holder 76 has an arm 80 (Fig. 4) with a protruding mounting flange 78. The flange 78 has openings for a mounting portion 82 for mounting the holder 76 to a mounting plate 84 above the stop 68. At one end of the holder 76 is a tongue 86 (Fig. 3) curving outward from the work surface. 70. The tongue 86 extends past the support member 61 and is above the narrow outlet end of the closure groove 55; the ends 53 of the edges of the closing plates 52 define the said outlet end. A longitudinal groove 88 is made in the holding portion 76 (Fig. 3). When the can is pushed from position C-3 to position C-4 (Fig. 3), the closure strip 26 and the closure strip 25 engage the tongue 86, whereby the strips 22, 25 and the strip 26 move together (Fig. 4). When the locking strips 22, 25 and the closure strip 26 are under the holding portion 76, the can is approximately in the position shown in Fig. 10.

Device 40 also has a compression and locking device. It is marked with the number 90 and has a mounting bracket (see especially Figures 1, 4 and 5). A rectangular rod-shaped support portion 94 for a press pad is provided in the guide groove 95 of the mounting bracket 92 so that it (94) can be pushed back and forth along its longitudinal axis in the groove 95. A rectangular plate-shaped press pad 96 made of stainless steel or the like is attached to the lower end of the support portion 94. At the bottom of the pad 96 there is a work surface 98 which adheres to the outer surface of the layers 10 71 090 to be locked. In the can structure shown in the figures, the work surface 98 adheres to the outer surface of the rear fields 7 along the strip 2 8 shown in Fig. 12. The compression pad 96 and support bar 94 reciprocate between the outer position (Figure 4), where they engage through the groove 88 between the outer surface of the upper layer of the can and the return position. The return position is at a certain distance from the layers of the can below the holding portion 76. The rod 64 reciprocates in the guide groove 95 according to the movement of the drive member 100. Movement-transmitting parts are arranged between the part 100 and the rod 94, so that the pressing pad §6 is made to move between the above-mentioned outer and return position according to the movement of the part 100. Em. the moving parts of the movement are knee joints 108 and 110.

The portion 100 is a piston rod in a cylinder 104 attached to a cylinder support bracket 106 (Figures 1 and 4). The cylinder 104 is connected to a source of compressed air (not shown) or some other source of pressurized fluid and is controlled in the usual manner so as to cause the drive member 100 to reciprocate in its axis. The hinge portion 108 is connected at its ice end (pivoting structure) to the mounting bracket 92 by a pin 112. The lower end of the portion 108 is in turn connected by a pin 116 (pivoting structure) to the upper end of the knee hinge portion 110 and a fork 102 made at the end of the drive rod 100. The lower end of the part is connected by a pin 114 (pivoting structure) to the upper end of the support pad 94 of the press pad.

When the cylinder 104 is forced to retract the drive rod 100 in the direction indicated by arrow 118 in Fig. 4, the knee members 108, 110 push the support member 94 upward in the direction indicated by arrow 119.

Thus, when the cylinder 104 is forced to protrude the portion 100 in the direction indicated by arrow 117 in Figure 4, the knee joints 108, 110 cause the portion 94 to protrude downward in the direction indicated by arrow 120 so that the surface 96 of the portion 96 protrudes through the groove 88 of the holding portion 76 and engages the outer surface. The console 92 has an adjustable set screw 118 which extends from the fork 102 and associated with the track portions 108 and 110, thereby preventing the operating portion 117 to indicate excessive movement of the arrow 100 direction. The screw 120 (Figures 4 and 5) is attached to the bracket 92 and contacts the upper circumferential edge of the part 108.

According to Figures 6 and 7, the work surface 70 of the stop 68 has elongate grooves 120 to 122 and 1.24 and transverse openings 126 and 128 so that the thickness of the strip 28 of can C can vary (Figures 11-12) and to ensure that the activated thermoplastic material flows into the can 11 71090 and fills each of the interlayer spaces between the strips 28 when po. the layers are pressed against the abutment work surface 70 through the horn and compression pad work surfaces 66 and 98. The grooves 120, 122 and 124 and the openings 126 and 128 operate in the same manner as the response described in U.S. Patent 3,910,014.

As previously mentioned, the horn 63 is attached to the housing 67 of the hit unit 62 so that it (63) moves to an outer, active position in which the sheet 64 extends through the groove 78 of the holding portion 76 through the outer surface 7 of the can C (along the strip 28); between the groove 88. The work surface 66 is then approximately in the position shown by the broken lines (point 66a) in Fig. 5.

Similarly, the compression pad 96 moves between the drive member 100 and the knee joint portions 108, 109 to an outer, active position where the sheet enters the groove 88 so that the work surface in the press pad 96 engages the outer surface of the rear field 7 along the can strip 28 (Figures 11-12). When the drive member has retracted, the compression pad 96 returns to its 1. rest position, which corresponds approximately to that indicated in Fig. 5 96a.

When the device is in use the cans are transferred in succession to the left (Figure 3) 50 points in the direction of the arrow C l - 07 above.

As the cans move from the wide end of the groove 55 to its narrow end at the support portion 61, the fields of the upper closure portion of the can C bend approximately from the position shown in Fig. 9 to the position shown in Fig. 10. When the closure strip 26 and the locking strips 22, 25 contact the tongue 86 of the holding part 76, the protruding part formed by the locking strips 22, 25 and the closing strip 26 (Fig. 10) is pressed into the space between the holding part 76 and the stop 68 work surface 70. When the can enters the wish station 58 (position 05, Fig. 3), it contacts a microswitch or some other control part connected to the control part of the welding unit 40. The horn sheet 64 begins to oscillate at a predetermined frequency (e.g., 20,000 Hz) and then moves from its rear position to its forward position where the work surface 66 passes through the groove 88 and contacts the outer surface of the can end closure layer in the area indicated by strip 28 in Figures 11,12. The vibration of the horn provides sufficient frictional heat to activate the thermoplastic coating of the can along the strip 29 (ensuring the flow of thermoplastic material). When the horn is activated to vibrate when it is attached to the outer surface of the paperboard layers for a predetermined length of time (e.g. 0.15 sec.), Horn activation ceases, as does vibration, while the horn remains compressed in the above layers again for a predetermined time 12 71,090 (e.g. sec.) so that the thermoplastic partially solidifies and begins to form a "lock". The coolant flowing through the channels 72 and 74 of the stop 68 then facilitates partial solidification. The horn then detaches from the paperboard layers and the retaining portion 76 prevents the layers from detaching from each other, even though the thermoplastic has not yet completely solidified. The transport device then pushes the can to the pressing and locking station 60 (position C-6, Fig. 3).

The holding portion 76 adheres to the outer surface of the cartons and prevents them from detaching from each other as the can moves from the activating station 58 (position C-5) to the pressing and locking station 60 (position C-6).

The can effect the entry. Station 60 (aeento C-6), cylinder 104 is forced työntämääi driving part 100 out of the to-ny puristustyy 96 moves in the direction of arrow 120 (Figure 4) forward position as illustrated by Figure 5 in the direction indicated by the background eft-nostaan. The work surface 98 of the compression pad 96 adheres to the outer surface of the layers along the strip 28 and compresses these between the work surfaces 98 and 70 with a predetermined amount of pressure and also for a predetermined time so that the thermoplastic material can solidify completely and form the above locking function. The length of the compression and locking period corresponds approximately to the activation period. Em. in the structural example, the horn is pressed into the cardboard layers for 0.40 sec. whereby it oscillates from this time for 0.15 sec. and is only compressed into layers for the remaining time, i.e. 0.25 sec. Po. the work cycle is thus 0.40 sec.

When the can enters the C-5 position at the activation station 58, it contacts a microswitch or other control device, whereupon the activation cycle begins, after which (1) the horn in the rear position is "tuned" in successive stages so as to oscillate at a predetermined frequency, e.g. 000 Hz, (2) the activated, oscillating horn moves to its anteriorly extended position, where the work surface 66 comes through a groove 88 in press contact with the outer surface of the layers to be locked (welded) along the strip 28, (3) horn activation ends after a predetermined time , the time is long enough to activate the thermoplastic material along the strip 28 (4) the dormant horn is compressed in the above layers again for a predetermined length of time so that the thermoplastic partially solidifies along the strip 28 and (5) the horn returns to its rear-to-rest position. in the example described above, the first, predetermined amount of time the set time when the horn is activated can be 0.15 sec. and the second predetermined time during which 13 71 090 the horn is dormant but still continuously compressed into the paperboard layers may be 0.25 sec. The entire activation period therefore takes 0.40 sec.

As the horn retracts to its rear position, the conveying device gradually moves and pushes the can from the activating station 58 to the pressing and locking stations 60 (the can is then in position C-6) as shown in Fig. 3. The can touches the microswitch or other similar control device again when it enters position C-6. In this case, the air cylinder 104 pushes out the drive part 100 as well as the compression from the rear position of the pad 96 to the front-active position, whereby it is compressed in the can along the strip 28. At the belt 28, the paperboard layers are compressed between the work surfaces 98 and 70 for 0.40 sec. (length of the activation period), as in the example described above. The microswitch or some other leg part is arranged in each of the above-mentioned positions, so that if the can does not come to position C-5 or C-6, neither the horn nor the compression pad will grip the abutment surface 70.

Em. times i.e. 0.15, 0.25 and 0.40 sec. are only example times, so they in no way limit po. invention. Thus, times may vary depending on different operating conditions, materials, material strengths, can size, etc. At both stations 58 and 60, other cycles can be performed with the equipment now described.

In order to increase the cooling and solidification rate of the previously activated thermoplastic material, channels for water or other coolant may be provided in the press pad 96. Po. the liquid then circulates through the press pad while it is in operation and increases the rate at which heat is removed from the layers pressed between the work surfaces 98 and 70.

Po. in construction, the work surfaces 66 and 98 of the horn and compression pad are smooth and parallel to the plane of the work surface 70 of the stop 68. Both the horn and the compression pad continue to move between their front and rear positions on a track perpendicular to their respective work surfaces 66 and 98, respectively. The longitudinal axis of the cylinder 104 and the piston rod first drive portion 100 is perpendicular to the trajectory of the compression pad and therefore parallel to the planes of the work surfaces 98 and 70.

The invention is not limited to the structure described above and shown in the drawings, but may be modified within the scope of the following claims.

Claims (15)

A method for obtaining seals between layers of end closures for thermoplastic-coated cardboard cartons or the like by vibration welding, characterized in that each carton is moved to a position in which its end closure is between two separate working surfaces (66, 70) on a vibrating welding horns (63) and a support means (68), respectively, that the horn is triggered to activate it and cause it to vibrate at a predetermined frequency, that the working surfaces of the activated horn and the support member are caused to clamp from opposite hali about the end closure layer at a clamping pressure. within predetermined limits beyond the entire area of the layers between the working surfaces, that the activated horn is poured into the squeeze position for a predetermined period of time to activate the thermoplastic coating to float, that the horn is deactivated while in the squeeze position, and poured into the depressed state for a squeeze period. to allow partial solidification a v the activated thermoplastic, that the working surfaces of the deactivated horn and the supporting member are separated, that the carton with the partially activated thermoplastic is moved to a cooling and squeezing station (60) with the end closure arranged between separate working surfaces (98, 70) -the pad (96) and the support member (68), that the working surfaces of the pressure pad and the support member are shifted from opposite halls to engagement with the end closure layer at a predetermined clamping pressure, that the pressure pad is poured into the clamping position for a predetermined period of time to allow complete setting of the thermoplastics on the pressure pad and the support member are disassembled to allow displacement of the cardboard end closure from the pinch and seal station. Apparatus for carrying out the method according to claim 1 for effecting a seal between layers of a carton (c) of thermoplastic coated cardboard material or the like, in which the thermoplastic material of the layers in the sealing area serves as a sealant and is activated by frictional heat from a vibrating weld horn (63) and thereupon allowed to cool and solidify under pressure to form sealing between the layers, characterized by a support member (68) having a working surface (70) for engagement with an outer surface of the layers of the sealed 19 71 090 sealing area, a pouring means (76) overlying the supporting means (68) for engaging the opposite outer surface of the layers to bond the layers together with the supporting means (68), a pressure pad (96), which has a working surface (98) for engagement with the opposite outer surface of the layers and is located opposite the working surface of the support member (68) and is movable with respect to the supporting member (68) between a the retracted, inactive position and an extended active position, in which the opposite working surfaces of the printing pad (96) and the supporting member (68) engage the sealing layers in a clamping relationship, the printing pad (96) being slidable from a retracted, inactive position to an extended active position, since the layer of cardboard end closure with activated thermoplastic is placed between the working surfaces of the printing pad (96) and the support member (68) to clamp the layers of activated thermoplastic and return to the retracted, non- active state after being maintained in the active state for a predetermined period of time, which is sufficient to allow the activated thermoplastic to cool and solidify. 3. Apparatus according to claim 2, characterized in that the pouring means (76) consists of an elongated plate with a slot (88) for exposing the outer surface of the part of the layers to be sealed, and permitting engagement of the working surface of the printing pad (96) with this outer surface. 4. Apparatus according to claim 2 or 3, characterized in that the pouring means (76) are formed with a guide tongue (86) at one end for guiding the layers to be sealed into the space between the pouring means (76) and the supporting means (68). ) in and for joining the layers. Apparatus according to any one of claims 2 ... 4, characterized by a mounting bracket (92) for the pressure pad (96) and a movement transmitting means (108, 110) coupled between the mounting bracket (92) and the pressure pad (96). to operate the pressure pad between its retracted and extended positions. 6. Apparatus according to claim 5, characterized by a movable operating means (100) coupled to said movement-transmitting means (108, 110) to actuate the pressure pad (96) between its retracted and extended positions in response to the movement of the operating means. (100). 20 71 090 Apparatus according to claim 6, characterized by a support rod (94) for the pressure pad (96), so mounted on one end of the rod (94), said movement-transmitting means (108, 110) being connected to the other end of the supporting rod (94), and a guide slot (95) in the pressure pad mounting bracket (92) for guiding the support rod (94) of the pressure pad (96) in a path perpendicular to the support surface of the support member as the pressure pad (96) moves between the extended and the retracted position. 8. Apparatus according to claim 7, characterized in that said movement-transmitting means (108, 110) comprise a knee-lifting device which is coupled between the mounting bracket (92) and the support rods (94) of the pressure pad (96). 9. Apparatus according to claim 8, characterized in that the knee-lifting device (108, 110) has a pair of knee joints, one end of which is coupled to the mounting bracket (92) and the other end of which is connected to the other end of the push rod support (96). (94) and that one end of the operating means (100) is pivotally connected to said knee joint means in the pivotal connection of the means with each other. 10. Apparatus according to any one of claims 6 to 9, characterized by a motor device (104) for effecting movement of the operating means (100) in a path substantially parallel to the plane of the working surface of the supporting means (60). and perpendicular to the path of movement of the printing pad (96). 11. Apparatus according to claim 10, characterized in that the motor device (104) consists of a piston and cylinder assembly and that the operating means (100) consists of the piston and cylinder assembly of the piston and cylinder assembly. 12. Apparatus according to any one of claims 2 ... 11, characterized in that the working surface (70) of the support member (68) is formed with longitudinal latches (120, 122, 124) and transverse latches (126, 128). ) to accommodate variations in the thickness of the layers in the sealing area. Apparatus according to any one of claims 2 to 12, characterized in that channels (72) are formed in the interfering means (68) for passing cooling fluid therethrough and for removing heat from its working surface.